No, the two parks are not identical twins.
In no way am I the expert on thins Disney, but having done both, here are a few differences:
Adventureland -
Jungle Cruise - Both
Indiana Jones - DisneyLAND only (uses similar ride system to Dinosaur at AK)
Tiki Room - I think DisneyLAND still shows the classic show, DisneyWORLD has "Under new management" with Iago and Zazu
Treehouses - DisneyLAND is themed to Tarzan, DisneyWORLD is themed to Swiss Family Robinson
Pirates of the Carinean - both parks have, but DisneyLANDs is much better and is located in their New Orlleans Square section.
Flying Carpets - DisneyWORLD only
Fronterland -
Big Thunder Mountain - both parks
Tom Sawyer Island - both parks
Country Bear Jamboree - DisneyWORLD only
Shooting Gallery - both parks
Liberty Square (DisneyWORLD, New Orleans Square (DisneyLAND)
Haunted Mansion - both houses are slightly different
Hall of Presidents - DisneyWOLRD only - (DisneyLAND has Great Moments with Mr. Lincoln on Main Street)
Riverboats - both parks, though DisneyLAND also has the sailing ship Columbia
Fantasmic! - DisneyLAND only, (it's located at Disney Studios in Florida)
Critter Country - DisneyLAND only, star attraction is Splash Mountain which is also at DisneyWORLD in Frontierland.
Fantasyland - this is where DisneyLAND shines
Small World - much better at DisneyLAND
Carousel - both parks
Mad Tea Party - both parks
Dumbo - both parks
Peter Pan - both parks
Snow White - both parks
Pinochio (as a ride) - DisneyLAND only
Mr. Toads Wild Ride - DisneyLAND only
Alice in Wonderland - DisneyLAND only
Casey Jr. Circus Train - DisneyLAND only
Storybook Land Canal Boats - DisneyLAND only
Sleeping Beauty walk-through - DisneyLAND only
Matterhorn Mountain - DisneyLAND only
(note: I think Disneyland added Winnie the Pooh since my visit, I don't know if that replaced one of the rides listed above)
Winnie the Pooh - both parks
Mickey's Phillharmagic - DisneyWORLD only
Toontown
Both toontowns are vastly different, while both offer character meet and greets, and a kiddie coaster (themed to Go-Gadget in DisneyLAND, and Goofy's Barnstormer in DisneyWORLD), DisneyLAND offers Roger Rabbits Cartoon Spin which is not offered in DisneyWORLD)
Tommorowland
Race Car Ride - Indy Speedway at DisneyWORLD, Autopia in DisneyLAND
Tommorowland Transit Authoirty - DisneyWORLD only
Inovations - DisneyLAND only (located at EPCOT in Flordia)
Carousel of Progress - DisneyWORLD only
Honey I Shrunk the Audience - DisneyLAND only (located at EPCOT in Florida)
Star Tours - DisneyLAND only - (located at Studios in Florida)
Space Mountain - Two diffferent rides, one at each park, similar but different
Astro Orbiter - both parks, thogh WORLD's is mounted on top of Rockettower Plaza, and LAND's is ground level
Buzz Lightyears Space Ranger SPin - DisneyWORLD only
Stitch's Great Escape - DisneyWORLD only
Timekeeper - DisneyWORLD only
Monorail - Tommrowland ride at DisneyLAND, transportation from parking lot to park at DisneyWORLD.
Main Street - similar but different, has Great Moments with Mr.. Lincoln at DisneyLAND only. Also DisneyLAND may still have its cinema open, i'm not sure.
Both parks have a train ride around the park, stops
WORLD - Main Street, Frontierland, Toontown
LAND - Main Street, New Orleans Square, Toontown (?), Tommorowland, has the Primevil and Grand Canyon dioramas at DisneyLAND only.
Both offer Fastpass
Feel free to correct me memory!